A known part-mounting apparatus is used for mounting a film-shaped electronic part, such as a FPC (flexible printed circuit), a COF part (chip-on-film part) or a TCP (tape carrier package), on a glass substrate in fabricating a flat panel display such as a liquid crystal panel.
FIG. 6 shows, by way of example, a glass substrate with electronic parts that are mounted thereon by such a part-mounting apparatus. As shown in FIG. 6, a glass substrate 21 is formed by laminating two sheets 21a and 21b respectively having different sizes. A plurality of electronic parts 22 are mounted on the front and back surfaces of a peripheral portion of the glass substrate 21, i.e., the lower surface of the upper sheet 21a and the upper surface of the lower sheet 21b. 
The glass substrate 21 thus provided with the electronic parts 22 is transferred from one process to another process by a substrate carrying apparatus 30 as shown in FIGS. 7A and 7B. Referring to FIGS. 7A and 7B, the substrate carrying apparatus 30 has an arm body 31 capable of vertical and lateral movement, and a plurality of suction pads 32 provided on the lower surface of the arm body 31 and capable of sticking to the upper surface of a glass substrate 21 by suction to hold the glass substrate 21. The substrate carrying apparatus 30 holds the glass substrate 21 (the glass substrate 21 with electronic parts 22 mounted thereon) by the suction pads 32 and carries the glass substrate 21 from one process to another process.
Recently, the dimensions of glass substrates for flat panel displays have progressively been increased and the dimensions of electronic parts mounted on the glass substrates have increased accordingly. Recent electronic parts to be mounted on the glass substrates include those having large outside dimensions and connected to a printed wiring board and a heat sink. When the substrate carrying apparatus 30 shown in FIGS. 7A and 7B carries a glass substrate 21 with such electronic parts 22 mounted thereon, the electronic parts 22 are caused to hang down from the glass substrate 21 by their own weight. Thus, there is a possibility that the hanging electronic parts 22 drop down during conveyance due to interference with other units or vibrations that act thereon (FIG. 7A). Moreover, there is a possibility that the electronic parts 22 are caused to strike against the glass substrate 21 due to vibrations that act thereon and thereby the glass substrate 21 is damaged (FIG. 7B).
Therefore, in the case of carrying a large glass substrate for a flat panel display or the like, it is a general method to place on a tray 33 a glass substrate 21 with electronic parts 22 mounted thereon, as shown in FIG. 8, and to carry the tray 33 holding the glass substrate 22 by a carrying arm or a carrying stage.
The tray 33 for carrying a large glass substrate is large and heavy. Therefore, it is difficult to handle the tray 33 manually and hence an additional tray handling mechanism for handling the tray 33 is necessary for returning the tray 33 from the succeeding process to the preceding process. The tray handling mechanism needs a space for installation and increases costs. Trays of different sizes must be used for fabricating different types of flat panel displays, i.e., for carrying glass substrates having different sizes, which increases the running cost.